A Kaiser Permanente study confirms the benefit of nirmatrelvir-ritonavir, also known as Paxlovid, as an early-stage treatment to prevent hospitalization for people with mild to moderate COVID-19, regardless of prior immunity or age. The study was published March 15, 2023, in Lancet ID.
“Among Kaiser Permanente members in Southern California who tested positive for coronavirus infection, receiving Paxlovid within 5 days of the start of COVID-19 symptoms was associated with substantial reductions in the risk of hospital admission or death,” said Sara Tartof, PhD, the senior author of the study and an epidemiologist with the Kaiser Permanente Southern California Department of Research & Evaluation. “These findings are even more notable because in this population with high levels of vaccination, we still see additional benefits of this treatment.”
Paxlovid is an oral therapeutic drug aimed at reducing the risk for severe outcomes of coronavirus infection. It is manufactured by Pfizer Inc. It currently has emergency use authorization by the U.S. Food and Drug Administration for adults and children 12 and older who are at high risk for progression to severe COVID-19.
The study analyses included patients with positive results from coronavirus tests undertaken in outpatient settings between April 8 and October 7, 2022. In the study population, 7,274 people had received Paxlovid, and 126,152 had not received Paxlovid. It was a time dominated by the omicron subvariants BA.2, BA.4, and BA.5. Overall, 86% of the 133,426 participants had received 2 COVID-19 vaccine doses, and 61% had received 3 or more.
The study found:
“Our data showed that the sooner people take Paxlovid upon symptom onset, the more effective the medication can be,” Tartof said. “However, there is still some benefit to treatment 6 or more days after symptom onset. People should talk with their doctors about the best approach for them.”